On March 13,1930, a conference will meet at The Hague to make progress in the codification of international law about territorial waters. Implicit in the plans for this meeting are two assumptions. The first, that it is better to codify the law rather than to follow the road traveled by the American Law Institute and “ restate” it. The second, that codification may more wisely be expressed in spatial than in causal terms. As to the first assumption, is it right? As to the second, it is submitted that, irrespective of whether one is drafting a custom or a code, the particular subject of territorial waters should be examined and set forth in causal rather than in spatial terms. It is submitted that the law of territorial waters has been, is, and in its nature must remain a thing of custom, not statute or treaty, and that any attempt to treat it differently will have the effect which thirtyfour years ago the late F. W. Maitlan prophesied was to be expected from the excesses of restricting by putting enactments into constitutions in the United States. “ First,” he said, “ you will get the effect of a dam,—and then you will get the effect of a flood.” Both have been seen.